SOFTSUSY - supersymmetric/Higgs spectrum and decays

by: B C Allanach, P Athron, A Bednyakov, M Bernhardt, T Cridge, D Grellscheid, M Hanussek, C H Kom, S Martin, D Robertson, R Ruiz de Austri, P Slavich, L Tunstall, A Voigt and A G Williams


This program provides a SUSY spectrum in the NMSSM, or the MSSM including flavour violation and with or without R-parity consistent with input Standard Model fermion mass/mixings and electroweak/strong coupling data. The R-parity violating mode can calculate neutrino masses and mixings to 1 loop. SOFTSUSY can be used in conjunction with other programs for many different particle physics calculations. SOFTSUSY now has a mode with 3 loop RGEs and some 2-loop threshold correction and 2-loop SUSY QCD corrections to gluino and squark pole masses. SOFTSUSY now computes decay branching ratios for the MSSM and NMSSM. It also ships with (and links to) Himalaya-1.0 for three-loop corrections to mh0.


Previous releases (4.1.13 and before) can be obtained from the old website

Quick Installation and Run Test

See for quick installation and run-test instructions.

For other ultra-basic instructions, see the introduction video. Otherwise, see a quick tutorial given at BUSSTEPP 2012.

Note that the executables are actually wrapper scripts, the “true” executables lie in the directory .libs/.


If you use SOFTSUSY to write a paper, please cite (see MCnet guidelines) - collected in soft.bib the manuals (up-to-date manuals included with distribution in doc subdirectory):

  1. rpcManual.pdf is the main one for the R-parity conserving MSSM: the base for all others: B.C. Allanach, Comput. Phys. Commun. 143 (2002) 305-331, hep-ph/0104145
  2. decays.pdf details calculations of sparticle and Higgs decays in the MSSM/NMSSM: B.C. Allanach and T. Cridge, Comput. Phys. Comm. 220 (2017) 417, arxiv:1703.09717
  3. nmssmManual.pdf describes the NMSSM implementation: B.C. Allanach, P. Athron, L. Tunstall, A. Voigt and A. Williams, Comput. Phys. Comm. 185 (2014) 2322, arXiv:1311.7659
  4. rpvManual.pdf for R-parity violating generalisation: B.C. Allanach and M.A. Bernhardt, Comput. Phys. Commun. 181 (2010) 232, arXiv:0903.1805
  5. neutManual.pdf on the one-loop calculation of neutrino masses and lepton mixing in the R-parity violating MSSM: B.C. Allanach, M. Hanussek and C.H. Kom, Comput. Phys. Commun. 183 (2012) 785, arXiv:1109.3735
  6. threeLoop.pdf describes the inclusion of three-loop MSSM RGEs and two-loop threshold corrections: B.C. Allanach, A. Bednyakov and R. Ruiz de Autri, Comput. Phys. Commun. 189 (2015) 192, arXiv:1407.6130
  7. ho.pdf describes the inclusion of two-loop SUSYQCD corrections to squark and gluino pole masses: B.C. Allanach, Stephen P. Martin, David G. Robertson and Roberto Ruiz de Austri, Comput. Phys. Commun. 05 (2017) 006, arXiv:1601.06657

Particle Decays

An example point including the calculation of sparticle decays, neglecting modes with a branching ratio of less than 1.0e-5, and outputting the partial widths in the comments:

./softpoint.x gmsb --n5=2 --mMess=1.0e6 --LAMBDA=5.0e5 --tanBeta=10 --sgnMu=1 --decays --minBR=1.0e-5 --outputPartialWidths

For queries regarding decay calculations please contact Tom Cridge

Three Loop Corrections to the Lightest CP Even Higgs Mass

For Himalaya-1.0 three-loop corrections to mh0, you must first install the package Eigen. Then do:

./configure CPPFLAGS="-I/usr/include/eigen3" --enable-two-loop-gauge-yukawa-compilation --enable-himalaya; make

After this, setting the SLHA SOFTSUSY BLock parameter 7 (number of Higgs mass loops) to 3 will include the corrections. If you use this option, you should cite [1], [6] and

SOFTSUSY-specific input for SUSY Les Houches Accord input files

Block SOFTSUSY           # SOFTSUSY specific inputs
  1   <TOLERANCE>        # desired fractional accuracy in output
  2   <MIXING>           # quark mixing option
  3   <PRINTOUT>         # gives additional verbose output during calculation
  4   <QEWSB>            # change electroweak symmetry breaking scale
  5   <INCLUDE_2_LOOP_SCALAR_CORRECTIONS>    # Full 2-loop running in RGEs
  6   <PRECISION>        # number of significant figures in SLHA output
  7   <numHiggsLoops>    # number of loops in REWSB/mh calculation
  8   <susyRpvBCatMSUSY> # Switch MSUSY-scale RPV boundary conditions ON
  9   <invertedOutput>   # RPV neutrino output uses normal hierarchy (=0.0) or inverted (=1.0)
 10   <forceSlha1>       # if =1, tries to force output into SLHA *1* format
 11   <m32>              # sets gravitino mass to m32
 12   <printSpectra>     # Prints spectrum even when point is theoretically excluded if=1
 13   <mAFlag>           # If=0 (default), sets tachyonic mA=0, otherwise mA=sqrt(|mA|^2)
 15   <NMSSMTools>       # If=1, enables NMSSMTools compatible SLHA2 output
 16   <MICROMEGAS>       # Micromegas options for NMSSMTools use: 1=RD, 2=DD, 3=ID, 4=both
 17   <NMSDECAY>         # If=1, flags for sparticle decays to be calculated via NMSDECAY
 18   <SoftHiggsOut>     # If=1, then the EWSB conditions output soft Higgs masses in NMSSM
 19   <threeLoopRGEs>    # If=1, then 3-loop MSSM RGEs included (default of 0 to disable)
 20   <gyThresholds>     # If>0, switch on gauge/Yukawa two-loop thresholds (see manual [6] for details). If=31, they all are switched on (default 0 to disable).
 22   <2-loop squark/gluino>   # Include 2-loop terms in gluino/squark masses (default of 0 to disable)
 23   <expandAroundGluinoPole> # sets expandAroundGluinoPole parameter (default 3)
 24   <minBR>                  # If decay BR is below this number, don't output that mode
 25   <threeBodyDecays>        # If set to 0, don't calculate 3-body decays (1=default)
 26   <outputPartialWidths>    # If set to 1, output partial widths (0=default)
 27   <MQEDxQCD>    # Set scale at which QEDxQCD is matched to MSSM (mt=default)

High orders mode

If the 2-loop SUSY QCD corrections to squark and gluino masses are required, do

./configure --enable-two-loop-sparticle-mass-compilation

An example point using the higher order terms can be run with, for example,

./softpoint.x sugra --tol=1.0e-4 --m0=1000 --m12=1000 --a0=0 --tanBeta=10 --sgnMu=1 --two-loop-sparticle-masses --two-loop-sparticle-mass-method=1

High accuracy mode

If the high accuracy mode with 3-loop RGEs and some 2-loop threshold corrections is required, do

./configure --enable-full-susy-threshold-compilation --enable-three-loop-rge-compilation

An example point using the high accuracy mode can be run with, for example,

./softpoint.x sugra --tol=1.0e-5 --m0=7240 --m12=800 --a0=-6000 --tanBeta=50 --sgnMu=1 --mt=173.2 --alpha_s=0.1187 --mbmb=4.18 --two-loop-susy-thresholds --three-loop-rges

See [6] for more details.

Executable files: after installation

Input and information files

Files included in this distribution

Source files are to be found in the src/ subdirectory. The inOutFiles/ directory contains input and output files. doc/ contains the manuals (see above).

Comparisons with other SUSY spectrum generators

There are detailed comparisons between SOFTSUSY and other publicly available programs in

and comparisons with NMSSM generators in


SOFTSUSY Copyright (C) 2007 B.C. Allanach

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

See licenses